GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 2003 🢒 Aurora 🢒 Engine 🢒 Engine Controls - 4.0L 🢒 DTC P0036

Circuit Description

The heating elements inside the heated oxygen sensors (HO2S) minimize the time required for the sensors to reach operating temperature, and then provide an accurate voltage signal. The powertrain control module (PCM) controls the HO2S heater operation with a low side driver. The HO2S bank 1 sensor 2 heater diagnostic monitors the current draw through the HO2S low side driver. The sensor receives power from a fused ignition 1 voltage circuit. If the PCM detects that the HO2S bank 1 sensor 2 heater low control circuit condition is incorrect, DTC P0036 will set.

Conditions for Running the DTC
    • The system voltage is between 9-18 volts.
    • The ignition is ON.

Conditions for Setting the DTC

The PCM detects an incorrect circuit condition for the commanded state of the low side driver.

Action Taken When the DTC Sets
    • The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC
    • The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with a scan tool.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  1. Turn ON the ignition, with the engine OFF.
  2. Clear the DTCs with a scan tool.
  3. Turn OFF the ignition.
  4. Turn ON the ignition, with the engine OFF.
  5. Observe the DTC Info parameter with a scan tool for at least 30 seconds.

Did DTC  P0036 fail this ignition?

Go to Step 4

Go to Step 3

3
  1. Start the engine.
  2. Allow the engine to idle at operating temperature for 30 seconds.
  3. Observe the DTC information with a scan tool.

Did DTC P0036 fail this ignition?

Go to Step 7

Go to Intermittent Conditions

4

Important: Use a known good ground. Do not use the heated oxygen sensor (HO2S) heater low control circuit or the HO2S low signal circuit.

  1. Turn OFF the ignition.
  2. Disconnect the HO2S bank 1 sensor 2 harness connector.
  3. Probe the HO2S bank 1 sensor  2 heater ignition 1 voltage circuit, at the engine harness side of the HO2S connector with a test lamp that is connected to a good ground.
  4. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 5

Go to Step 11

5
  1. Turn OFF the ignition.
  2. Probe the HO2S bank 1 sensor 2 heater low control circuit with a test lamp that is connected to battery voltage. Refer to Probing Electrical Connectors in Wiring Systems.
  3. Turn ON the ignition, with the engine OFF.
  4. Command the O2S heater driver 4 ON and OFF with a scan tool.

Does the test lamp flash ON and OFF?

Go to Step 9

Go to Step 6

6

Test the HO2S bank 1 sensor 2 heater low control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 10

7

Important:  Disconnection of the powertrain control module (PCM) during testing may eliminate the voltage source that caused this fault.

Test the HO2S bank 1 sensor 2 heater low control circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 8

8

Test the HO2S bank 1 sensor 2 low control circuit for a short to the HO2S heater ignition 1 voltage circuit at the sensor side of the HO2S harness connector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Is the circuit shorted?

Go to Step 12

Go to Step 10

9

Test for an intermittent and for a poor connection at the harness connector of the HO2S bank 1 sensor 2. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 12

10

Test for an intermittent and for a poor connection at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 13

11

Repair the open or high resistance in the HO2S bank 1 sensor 2 heater ignition 1 voltage circuit.

Did you complete the repair?

Go to Step 14

--

12

Replace the HO2S bank 1 sensor 2. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 .

Did you complete the replacement?

Go to Step 14

--

13

Replace the PCM. Refer Powertrain Control Module Replacement .

Did you complete the replacement?

Go to Step 14

--

14
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 15

15

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK